Stairwell sign from the World Trade CenterDescription: This damaged floor marker, labeled “Stairwell C, Floor 102,” was recovered from the debris of the World Trade Center.

Context: In a high-rise building, many people ignore the stairs until an emergency. For those below the impact zones in the World Trade Center, the stairs proved to be a lifeline to safety—about 20,000 people escaped the building. Above the impact zone in the north tower (floors 94 through 98), there was no hope as all three stairwells were blocked by fire and debris. Above the impact zone in the south tower (floors 78 through 84), those who did not evacuate immediately in the 17 minutes after the north tower crash had an extremely limited chance to escape through one partially blocked stairwell. Many believe that building improvements and training procedures following the 1993 bombing helped save many lives on September 11.

North tower stairwell during evacuationBy all reports the evacuation in the World Trade Center stairwells was orderly and quiet. Descending office workers would step aside and often cheer as the firefighters carrying a heavy load of equipment ascended.